Page 70 - Sace Emax 2 Catalogue

4/6 SACE EMA X 2 LOW VOLTAGE AIR CIRCUIT-BRE AKERS

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Load Shedding

Emax 2 has built-in load shedding algorithms to avoid power
unbalance in the low voltage plant and stress for all the components.

Purpose All the versions are available on Emax 2 platform for
ABB Emax 2 embeds patented functions based on both the Microgrid situations, sharing some infor-
load shedding which reduces the Microgrid stress mation about the loads under control in the plant.
in all situations. Typically it is the main protection
relay of the low voltage Microgrid located at the Application examples
interface point with the medium voltage grid, • Grid-connected plants with running GenSets,
able to control the plant in every circumstances. which contribute to the self-consumption to-
gether with potential renewable sources and
Microgrid in islanding operation support the load power supply in emergency
After the Emax 2 circuit breaker opens, because conditions. It is the case of hybrid PV-diesel re-
of interface protection systems intervention or mote communities connected to weak distribu-
external command, the Microgrid should transit tion-grids where there are a lot of daily faults,
from on-grid to off-grid state with bumpless or of facilities located in geographical areas
transition. When it is standalone, the power ab- where there are frequent environmental events,
sorption from the main grid ceases, so that the for example hurricanes or earthquakes.
Microgrid loads remains supplied by the local • Grid-connected plants with back-up GenSets
generation, like diesel GenSet or energy storage started up after main - gen transfer switching
systems. This Microgrid generation can be always logics that require high reliability. For example,
active or started up by an automatic transfer hospitals, banks or data centers.
switching (ATS) logic after the disconnection
from the main grid, depending on the plant con- Benefits
figuration. During the islanding transition, it is Thanks to Emax 2 with embedded Load Shedding
very important to avoid the frequency drop, oth- innovation, the following benefits are guaranteed:
erwise the generation protections could trip Service continuity
jeopardizing the Microgrid stability with conse- • When a plant remain disconnected from the main
quently a long downtime. Emax 2, employing the grid, even if local production is present, there is
current and voltage measurements, integrates a significant stress that turns off all the genera-
two different fast load shedding logics to reduce tors with consequent blackout. Load Shedding
this blackout risk, protecting the Microgrid logics embedded in Emax 2 reduce the frequency
during the intentional or unintentional islanding drop that usually makes the local generation pro-
operation: tection trip, maintaining the plant live.

• Basic Load Shedding, simple logic able to rec-
ognize the Microgrid disconnection event and
shed a group of not priority loads thus ensuring
a fast time response and power balance.
• Adaptive Load Shedding, the advanced algo-
rithm available with Emax 2 as an enhancement
of the basic version. The intelligent software
embedded in the unit sheds very quickly the not
priority loads according to the Microgrid power
consumption and frequency measurements.
Moreover, such software has a dedicated con-
figuration for backup generation related to ATS
and the software itself is even able to estimate
the energy produced by a solar plant based on
plant geography settings.